| 摘要 |
PURPOSE: A nonvolatile memory device and an operation method thereof are provided to prevent the error of a read-out operation due to the change of a threshold voltage by measuring the threshold voltage change of a retention check cell and setting the read-out voltage. CONSTITUTION: A nonvolatile memory device which includes a plurality of main cells and retention check cells is provided. A plurality of main cells and retention check cells are programmed(320). The number of a fail bit is counted by reading out a plurality of retention check cells(330). The counted fail bit number and a preset bit number are compared(340). When the counted fail bit number is less than the preset fail bit number, a first read-out voltage is set(350). When the counted fail bit number is greater than the preset fail bit number, a second read-out voltage is set(360). A plurality of main cells are read out by using the first or the second read-out voltage(370).
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